Glutathione Peroxidase Research Articles

PPT1 Promotes Growth and Inhibits Ferroptosis of Oral Squamous Cell Carcinoma Cells.

Oral squamous cell carcinoma (OSCC) is one of the most prevalent cancers with poor prognosis in the head and neck. Elucidating molecular mechanisms underlying OSCC occurrence and development is important for the therapy. Dysregulated palmitoylation-related enzymes have been reported in several cancers but OSCC. To explore the role of palmitoyl-protein thioesterase 1 (PPT1) in OSCC. Differentially expressed genes (DEGs) and related protein-protein interaction networks between normal oral epithelial and OSCC tissues were screened and constructed via different online databases. Tumor samples from 70 OSCC patients were evaluated for the relationship between PPT1 expression level and patients'clinic characteristics. The role of PPT1 in OSCC proliferation and metastasis was studied by functional experiments including MTT, colony formation, EdU incorporation and transwell assays. Lentivirus-based constructs were used to manipulate gene expression. FerroOrange probe and malondialdehyde assay were used to determine ferroptosis. Growth of OSCC cells in vivo was investigated by a xenograft mouse model. A total of 555 DEGs were obtained, and topological analysis revealed that PPT1 and GPX4 might play critical roles in OSCC. Increased PPT1 expression was found to be correlated with poor prognosis of OSCC patients. PPT1 effectively promoted the proliferation, migration and invasion while inhibited the ferroptosis of OSCC cells. PPT1 affected the expression of glutathione peroxidase 4 (GPX4). PPT1 promoted growth and inhibited ferroptosis of OSCC cells. PPT1 might be a potential target for OSCC therapy.

Mitigative role of herbacetin against polystyrene microplastics-instigated liver damage in rats

The environmental pollution of polystyrene microplastics (PS-MPs) is a raising global concern as it imposes adverse effects on the health of organisms. Herbacetin (HBN) is a natural flavone with diverse biological activities. Therefore, the study was intended to assess the curative role of HBN against PS-MPs provoked hepatic damage. 48 rats were divided into 4 groups, control, PS-MPs-intoxicated (0.01 mg/kg), PS-MPs + HBN co-treated (0.01 mg/kg + 40 mg/kg) and HBN only treated (40 mg/kg) group. The experiment was conducted for 30 day. PS-MPs administration lowered the expressions of Nrf-2 and anti-oxidants genes, although increased the Keap-1 expression. It also lessened the activities of superoxide dismutase (SOD), glutathione reductase (GSR), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and heme oxygenase-1 (HO-1) and glutathione (GSH) level, besides elevating the levels of MDA and ROS. Additionally, PS-MPs augmented alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine transaminase (ALT) levels. Furthermore, there was an upsurge in the levels of inflammatory indices in PS-MPs treated group. PS-MPs also upregulated Caspase-3 and Bax expression, besides suppressed Bcl-2 expression. Nevertheless, HBN therapy amended all the impairments due to its anti-apoptotic, anti-oxidant and anti-inflammatory, hepatoprotective nature. So, it might be anticipated that HBN can applied as a drug to cure hepatic toxicity.

Rhamnetin abrogates polystyrene microplastics prompted hepatic damage by regulating Nrf-2/Keap-1 pathway

Polystyrene microplastics (PS-MPs) are environmental toxicants that impose adverse effects on organisms. Rhamnetin (RHM) is a natural flavone that shows multiple therapeutic potentials. Therefore, the present study was planned to determine the mitigative effect of RHM against PS-MPs induced liver damage. 48 rats were divided into 4 groups. Control group, PS-MPs (0.01 mg/kg) administered group, PS-MPs (0.01 mg/kg)+ RHM (50 mg/kg) co-administered group and RHM alone (50 mg/kg) administered group. PS-MPs reduced the expressions of Nrf-2 and anti-oxidant gene expressions, whereas increasing the Keap-1 expression. PS-MPs also lowered the activities of catalase (CAT), glutathione reductase (GSR), heme oxygenase-1 (HO-1), glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH), besides elevated the MDA and ROS levels. Additionally, PS-MPs augmented alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) levels. Furthermore, there was an upsurge in the levels of inflammatory indices in PS-MPs treated group. PS-MPs intoxication also increased Bax and Caspase-3 expression, whereas lowering the Bcl-2 level. Nevertheless, RHM mitigated all the anomalies due to its hepatoprotective, anti-inflammatory, anti-oxidant and anti-apoptotic potentials. The supplementation of RHM regulates the apoptotic as well as inflammatory pathways and protects the liver from damage.

Aurantio‑obtusin regulates lipogenesis and ferroptosis of liver cancer cells through inhibiting SCD1 and sensitizing RSL3.

Ferroptosis, characterized by iron‑mediated non‑apoptotic cell death and alterations in lipid redox metabolism, has emerged as a critical process implicated in various cellular functions, including cancer. Aurantio‑obtusin (AO), a bioactive compound derived from Cassiae semen (the dried mature seeds of Cassie obtusifolia L. or Cassia toral L.), has anti‑hyperlipidemic and antioxidant properties; however, to the best of our knowledge, the effect of AO on liver cancer cells remains unclear. The Cell Counting Kit‑8, EdU staining and migration assays were employed to assess the anti‑liver cancer activity of AO. Intracellular levels of glutathione peroxidase 4 protein and lipid peroxidation were measured as indicators of ferroptotic status. Immunohistochemical analyses, bioinformatics analyses and western blotting were conducted to evaluate the potential of stearoyl‑CoA desaturase 1 (SCD1) in combination with ferroptosis inducers for the personalized treatment of liver cancer. The present study revealed that AO significantly inhibited the proliferation of liver cancer cells in vitro and in vivo. Mechanistically, AO inhibited AKT/mammalian target of rapamycin (mTOR) signaling, suppressed sterol regulatory element‑binding protein 1 (SREBP1) expression, and downregulated fatty acid synthase expression, thereby inhibiting de novo fatty acid synthesis. Further investigations demonstrated that AO suppressed glutathione peroxidase 4 protein expression through the nuclear factor erythroid 2‑related factor 2/heme oxygenase‑1 pathway, induced ferroptosis in liver cancer cells, and simultaneously inhibited lipogenesis by suppressing SCD1 expression through the AKT/mTOR/SREBP1 pathway. Consequently, this increased the sensitivity of liver cancer cells to the ferroptosis inducer RSL3. Additionally, the enhanced effects of AO and RSL3, which resulted in significant tumor suppression, were confirmed in a xenograft mouse model. In conclusion, the present study demonstrated that AO induced ferroptosis, downregulated the expression of SCD1 and enhanced the sensitivity of liver cancer cells to the ferroptosis inducer RSL3. The synergistic use of AO and a ferroptosis inducer may have promising therapeutic effects in liver cancer cells.

Preparation and characterization of cysteine-rich collagen peptide and its antagonistic effect on microplastic induced damage to HK-2 cells

Cysteine (Cys) plays a significant role in the stability and antioxidant capacity of peptide. This study was to prepare Cys-rich collagen peptide and evaluate its preventive effect on microparticle (MPs)-induced HK-2 cell damage. The results showed that the Cys-rich peptides (AMP-C) were successfully prepared from collagen hydrolysate by plastein reaction in the presence of exogenous Cys. The scavenging activities of 2,2-Diphenyl-1-picrylhydrazyl and hydroxyl radical of AMP-C were significantly higher than those of original peptides without Cys. The fraction with molecular weight < 3 kDa (AMP-CA) significantly improved MPs-induced damage and apoptosis of HK-2 cells. Compared with the same fractions lacking Cys (AMP-A), AMP-CA showed better performance in reducing reactive oxygen species and increasing the total superoxide dismutase and glutathione peroxidase levels, which may be related to its down-regulation of Kelch-like ECH-associated protein 1 (Keap1) expression. In addition, AMP-CA showed strong effects on inhibiting interleukin-6, tumor necrosis factor-α, monocyte chemoattractant protein-1, kidney injury molecule-1, and nuclear factor kappa-B levels. Finally, 330 Cys-containing peptides were isolated from AMP-CA, among which Leucine-Glycine-Asparagine-Glycine-Cysteine-Proline (LGNGCP) showed the lowest binding energy with Keap1 protein. In conclusion, the Cys-rich collagen peptide with higher antioxidant activity was successfully prepared by plastein reaction, which alleviated the HK-2 cells damage induced by MPs through antioxidant and anti-inflammatory. Our findings suggested that Cys-rich collagen peptide might be used as a functional food to mitigate health hazards associated with MPs accumulation.

Decreased ability to manage increases in reactive oxygen species may underlie susceptibility to arrhythmias in mice lacking Scn1b.

Scn1b plays essential roles in the heart, where it encodes β1-subunits that serve as modifiers of gene expression, cell surface channel activity, and cardiac conductivity. Reduced β1 function is linked to electrical instability in various diseases with cardiac manifestations and increased susceptibility to arrhythmias. Recently, we demonstrated that loss of Scn1b in mice leads to compromised mitochondria energetics and reactive oxygen species (ROS) production. In this study, we examined the link between increased ROS and arrhythmia susceptibility in Scn1b-/- mice. In addition, ROS-scavenging capacity can be overwhelmed during prolonged oxidative stress, increasing arrhythmia susceptibility. Therefore, we isolated whole hearts and cardiomyocytes from Scn1b-/- and Scn1b+/+ mice and subjected them to an oxidative challenge with diamide, a glutathione oxidant. Next, we analyzed gene expression and activity of antioxidant enzymes in Scn1b-/- hearts. Cells isolated from Scn1b-/- hearts died faster and displayed higher rates of ROS accumulation preceding cell death compared with those from Scn1b+/+. Furthermore, Scn1b-/- hearts showed higher arrhythmia scores and spent less time free of arrhythmia. Lastly, we found that protein expression and enzymatic activity of glutathione peroxidase is increased in Scn1b-/- hearts compared with wild type. Our results indicate that Scn1b-/- mice have decreased capability to manage ROS during prolonged oxidative stress. ROS accumulation is elevated and appears to overwhelm ROS scavenging through the glutathione system. This imbalance creates the potential for altered cell energetics that may underlie increased susceptibility to arrhythmias or other adverse cardiac outcomes.NEW & NOTEWORTHY Using an oxidative challenge, we demonstrated that isolated cells from Scn1b-/- mice are more susceptible to cell death and surges in reactive oxygen species accumulation. At the whole organ level, they were also more susceptible to the formation of cardiac arrhythmias. This may in part be due to changes to the glutathione antioxidant system.

Canagliflozin can improve cardiac function in HFpEF rats partly by regulating ferroptosis

Objective: To explore the effects of canagliflozin on cardiac function and its regulation of ferroptosis in rats with heart failure with preserved ejection fraction (HFpEF). Methods: Thirty-two 7-week-old Dahl salt-sensitive rats were selected and randomly divided into four groups: the control group (fed with low-salt diet), the HFpEF group (fed with high-salt diet), the canagliflozin 20 group (fed with high-salt diet and 20 mg·kg-1·d-1 canagliflozin), and the canagliflozin 30 group (fed with high-salt diet and 30 mg·kg-1·day-1 canagliflozin). Body weight and blood pressure of the rats in each group were monitored. Metabolic cage tests were conducted at the10th week of the experiment, and echocardiography was performed at the 12th week, after which the rats were killed. Blood and left ventricular samples were collected. HE staining, Masson staining, Prussian blue iron staining, and reactive oxygen species staining were performed to observe the cardiomyocyte size and shape, degree of interstitial fibrosis, iron staining, reactive oxygen species production under optical microscope. The ultrastructure of cardiomyocytes was observed under electron microscope. Western blotting and real-time fluorescent quantitative reverse transcription polymerase chain reaction (RT-qPCR) were used to detect the expression levels of proteins and mRNA related to ferroptosis in left ventricular myocardial tissue of rats in each group. Results: After 1 week of adaptive feeding, all rats survived. Metabolic cage results showed that compared with control group, rats in the HFpEF group, canagliflozin 20 group and canagliflozin 30 group had more food intake, water intake and urine output, and lower body weight (all P<0.05). These changes were more pronounced in canagliflozin 20 group and canagliflozin 30 group than in HFPEF group, and only the body weight at the 12th week showed a statistically significant difference between canagliflozin 20 group and canagliflozin 30 group (P<0.05). The blood pressure of 6th week and 12th week, heart weight and left ventricular corrected mass of 12th week of rats in HFpEF group were higher than those in control group, canagliflozin 20 group and canagliflozin 30 group, while the ratio of early mitral valve peak velocity to late mitral valve peak velocity of 12th week was lower (all P<0.05). HE and Masson staining showed that compared to control group, the myocardial fibers in the left ventricular myocardial tissue of rats in HFpEF group were disordered, with larger cell diameter ((0.032±0.004) mm vs. (0.023±0.003) mm, P<0.05), irregular shape, obvious proliferation of interstitial collagen fibers, and higher collagen volume fraction (0.168±0.028 vs. 0.118±0.013, P<0.05). Compared with HFpEF group, rats in the canagliflozin 20 group and canagliflozin 30 had more orderly arranged myocardial fibers, more regular cardiomyocyte shape, smaller cell diameter, and lower collagen volume fraction (P<0.05). It was observed under electron microscopy that, compared to control group, most of the striated muscles in myocardial tissue of HFpEF group were broken, and the Z line and M line could not be clearly distinguished, some changes such as mitochondrial swelling, membrane thickening, cristae reduction or even disappearance occurred. In the canagliflozin 20 group and canagliflozin 30 group, the arrangement of striated muscles in the myocardial tissue of rats tended to be more regular, and the morphological changes of mitochondria were milder. Prussian blue iron staining results showed that the iron content in myocardial tissue of rats in HFpEF group was higher than that in control group, canagliflozin 20 group and canagliflozin 30 group. Reactive oxygen species staining results showed that the reactive oxygen species content in the myocardial tissue of rats in HFpEF group was higher than that of control group, canagliflozin 20 group and canagliflozin 30 group. Biochemical analysis of myocardial tissue showed that Fe2+ and malondialdehyde content in myocardial tissue of rats in HFpEF group were higher than those in control group, canagliflozin 20 group and canagliflozin 30 group, while glutathione content was lower (all P<0.05). Western blot and RT-qPCR detection results showed that compared to control group, rats in HFpEF group had higher expression levels of transferrin receptor 1 (protein relative expression level: 1.37±0.16 vs. 0.31±0.12), acyl-CoA synthetase long-chain family member 4 (protein relative expression level: 1.31±0.15 vs. 0.63±0.09) protein and mRNA, and lower expression levels of ferritin heavy chain 1 (protein relative expression level: 0.45±0.08 vs. 1.41±0.15) protein and mRNA (all P<0.05). There was no statistically significant difference in these indicators between canagliflozin 20 group and the canagliflozin 30 group (all P>0.05). There was no significant difference in levels of glutathione peroxidase 4 protein and mRNA expression in myocardial tissue of rats in four groups(P>0.05). Conclusion: Canagliflozin improves cardiac function in HFpEF rats by regulating the ferroptosis mechanism.

Effects of inactivated Lactobacillus rhamnosus on growth performance, serum indicators, and colonic microbiota and metabolism of weaned piglets

BackgroundTo assess the effects of inactivated Lactobacillus rhamnosus (ILR) on growth performance, serum biochemical indices, colonic microbiota, and metabolomics in weaned piglets, 120 piglets were randomly divided into five groups. Samples in the control group were fed a basal diet, while the experimental ILR1, ILR2, ILR3, and ILR4 groups were fed basal diets supplemented with 0.1%, 0.2%, 0.3%, and 0.4% ILR, respectively. The prefeeding period lasted for 5 days and was followed by a formal period of 28 days.ResultsCompared to the control, the average daily gain increased by 4.38%, 7.98%, 19.32%, and 18.80% for ILR1, ILR2, ILR3, and ILR4, respectively, and the ratio of feed to gain decreased by 0.63%, 3.80%, 12.66%, and 10.76%, respectively. Serum IgA, IgG, IgM, total antioxidant capacity, and glutathione peroxidase levels increased significantly in weaned piglets in the treatment groups. Addition of 0.3% ILR significantly increased the Shannon and Simpson indices of the colonic microbiota in weaned piglets and altered the microbiota composition. Changes in metabolic profiles were observed and were primarily related to the urea cycle, amino acid metabolism, and lipid metabolism.ConclusionILR improved growth performance and serum immunological and biochemical indices and optimized the colonic microbiota structure and metabolism of weaned piglets.

NIR‐Triggered Cu2O/Cu2‐xS Heterostructure as an “All‐In‐One” Functional Nanoplatform for Efficient Synergistic Tumor Therapy

AbstractThe fabrication of synergistic multifunctional anti‐tumor nanoplatforms is challenging due to the urgent requirement to activate different therapeutic modalities. Although the multi‐modal treatments can be achieved by carrying out the activation with different exogenous and endogenous stimulations in sequence, this tedious manner is not applicable to the ideal synergistic cancer treatment. Herein, a simple heterojunction of Cu2O/Cu2‐xS modified with gambogic acid and hyaluronic acid (CCS@GA@HA) is ingeniously fabricated for the synergistic cancer treatment combining photothermal therapy (PTT), photocatalytic therapy (PCT), chemodynamic therapy (CDT) and potential ferroptosis just activated by the single near infrared (NIR) light irradiation. Cu2O/Cu2‐xS heterostructure (CCS) with promoted separation and transfer efficiency of photogenerated charge carriers exhibits excellent photocatalytic performance. The intervention of gambogic acid (GA) downregulates the overexpression of heat shock protein 90 (HSP90), which make it possible to execute the mild PTT. And the CDT performance is efficiently improved by the heat generated from PTT. Specifically, CCS appears to accelerate the accumulation of lipid peroxides (LPO) and inactivate glutathione peroxidase 4 (GPX4) that directly induce ferroptosis. In brief, CCS@GA@HA exhibits prominent NIR‐triggered synergistic effect involving PCT, mild PTT, enhanced CDT and ferroptosis for an effective multi‐modal tumor treatment.

Possible protective effect of remifentanil against testicular ischemia-reperfusion injury

Abstract Objectives This study aims to evaluate the protective efficacy of remifentanil against testicular ischemia-reperfusion injury. Methods The study included 24 male rats. The rats were randomized into three groups: Group 1 was the control group. Group 2 was subjected to a testicular torsion/detorsion model. Group 3 underwent similar procedures and additionally received remifentanil (0.6 μg/kg/min) intravenously for the first 20 min of reperfusion. Blood samples were taken for biochemical analyses, and orchiectomy was performed for histopathologic examination. Results Biochemical analysis of blood samples showed a significant increase in antioxidant enzyme activity, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in Group 3 compared to Group 2 (p:0.004 and p:0.002, respectively). There was a dramatic decrease in the levels of proinflammatory cytokines, including interleukin-1 beta (IL-1 Beta), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) in Group 3 compared to Group 2 (p:0.001, p:0.046, and p:0.004, respectively). Similarly, malondialdehyde (MDA) levels decreased in Group 3 compared to Group 2 (p:0.004). Histopathologic examination of Group 3 rats showed positive changes in inflammation, hemorrhage, edema, and congestion levels compared to Group 2 (p&lt;0.001). Similarly, there was a positive effect on the Johnsen and Cosentino score in Group 3 compared to Group 2 (p:0.001 and p&lt;0.001, respectively). Conclusions In our study, it has been documented that remifentanil protects against testicular ischemia-reperfusion injury.

Effect of Morchella esculenta polysaccharides on the rectal microbiota of mice challenged with lipopolysaccharides

IntroductionIntestinal dysfunction poses a severe problem by preventing the digestion and absorption of nutrients. The gut, being the most vital organ for these processes, plays a crucial role in ensuring our body receives the nutrients it needs. We explored the mitigating effect of Morchella esculenta polysaccharides (MEP) on intestinal injury induced by lipopolysaccharides (LPS) through the modulation of intestinal flora.MethodsFor this purpose, Kunming mice (KM) were divided into three groups, namely, PC, PM, and PY. Group PY was treated with MEP, while groups PM and PY were induced with LPS.ResultsThe results showed that weight loss in the PM group was significantly greater than that in the PY group (P &amp;lt; 0.05), and the organ indexes of the lung and spleen in the PM group were significantly higher than those in the PC (P &amp;lt; 0.01) and PY (P &amp;lt; 0.05) groups. LPS caused severe injuries in KM mice in the PM group, characterized by broken villi. However, MEP treatment could alleviate this damage in the PY group, resulting in relatively intact villi. The serum analysis showed that tumor necrosis factor alpha (TNF-ɑ) (P &amp;lt; 0.01), interleukin 6 (IL-6) (P &amp;lt; 0.01), and 3,4-methylenedioxyamphetamine (MDA) (P &amp;lt; 0.05) levels were significantly higher in the PM group, while IL-10 (P &amp;lt; 0.001), superoxide dismutase (SOD) (P &amp;lt; 0.01) and glutathione peroxidase (GSH-Px) (P &amp;lt; 0.01) were significantly lower in that group. Interestingly, supplementation with MEP could lower the levels of TNF-ɑ, IL-10, IL-6, MDA while increasing the levels of superoxide dismutase (SOD) (P &amp;lt; 0.01) and GSH-Px. The gut microbiota analysis yielded 630,323 raw reads and 554,062 clean reads, identifying 3,390 amplicon sequencing variants (ASVs). One phylum and five genera were notably different among animal groups, including Escherichia_Shigella, Limosilactobacillus, unclassified_Geminicoccaceae, unclassified_Rhodobacteraceae, and Parabacteroides (P. distasonis).DiscussionIn conclusion, we found that MEP could mitigate the intestinal damage caused by LPS by modulating the inflammatory response, oxidative resistance, and intestinal flora of KM mice. Our results may provide insights into novel treatment options for intestine-related diseases.

All‐Atom Protein Sequence Design Based on Geometric Deep Learning

Designing sequences for specific protein backbones is a key step in creating new functional proteins. Here, we introduce GeoSeqBuilder, a deep learning framework that integrates protein sequence generation with side chain conformation prediction to produce the complete all‐atom structures for designed sequences. GeoSeqBuilder uses spatial geometric features from protein backbones and explicitly includes three‐body interactions of neighboring residues. GeoSeqBuilder achieves native residue type recovery rate of 51.6%, comparable to ProteinMPNN and other leading methods, while accurately predicting side chain conformations. We first used GeoSeqBuilder to design sequences for thioredoxin and a hallucinated three‐helical bundle protein. All the 15 tested sequences expressed as soluble monomeric proteins with high thermal stability, and the 2 high‐resolution crystal structures solved closely match the designed models. The generated protein sequences exhibit low similarity (minimum 23%) to the original sequences, with significantly altered hydrophobic cores. We further redesigned the hydrophobic core of glutathione peroxidase 4, and 3 of the 5 designs showed improved enzyme activity. Although further testing is needed, the high experimental success rate in our testing demonstrates that GeoSeqBuilder is a powerful tool for designing novel sequences for predefined protein structures with atomic details. GeoSeqBuilder is available at https://github.com/PKUliujl/GeoSeqBuilder

All-Atom Protein Sequence Design Based on Geometric Deep Learning.

Designing sequences for specific protein backbones is a keystep in creating new functional proteins. Here, we introduceGeoSeqBuilder, a deep learning framework that integratesprotein sequence generation with side chain conformationprediction to produce the complete all-atom structures fordesigned sequences. GeoSeqBuilder uses spatial geometricfeatures from protein backbones and explicitly includesthree-body interactions of neighboring residues. GeoSeqBuilderachieves native residue type recovery rate of 51.6%,comparable to ProteinMPNN and otherleadingmethods,while accurately predicting side chain conformations. Wefirst used GeoSeqBuilder to design sequences for thioredoxinand a hallucinated three-helical bundle protein. All the15 tested sequences expressed as soluble monomeric proteinswith high thermal stability, and the 2 high-resolutioncrystal structures solved closely match the designed models.The generated protein sequences exhibit low similarity(minimum 23%) to the original sequences, with significantlyaltered hydrophobic cores. We further redesigned the hydrophobiccore of glutathione peroxidase 4, and 3 of the 5designs showed improved enzyme activity. Although furthertesting is needed, the high experimental success ratein our testing demonstrates that GeoSeqBuilder is a powerfultool for designing novel sequences for predefined proteinstructures with atomic details. GeoSeqBuilder is availableat https://github.com/PKUliujl/GeoSeqBuilder.

Targeting ferroptosis for improved radiotherapy outcomes in HPV‐negative head and neck squamous cell carcinoma

To enhance the efficacy of radiotherapy (RT) in human papillomavirus (HPV)‐negative head and neck squamous cell carcinoma (HNSCC), we explored targeting ferroptosis, a regulated cell death process. We developed a gene signature associated with ferroptosis using Cox proportional hazard modeling in HPV‐negative HNSCC patients who underwent RT. This ferroptosis‐related gene signature (FRGS) was a significant predictor of overall survival and recurrence‐free survival in HPV‐negative HNSCC patients who received RT. Subtype B of the FRGS, characterized by decreased expression of ferroptosis inducers [nuclear receptor coactivator 4 (NCOA4) and natural resistance‐associated macrophage protein 2 homolog/divalent metal transporter 1 (NRAMP2/DMT1)] and increased expression of suppressors [phospholipid hydroperoxide glutathione peroxidase (GPX4) and ferritin heavy chain (FTH1)], was associated with poorer prognosis, potentially indicating the inhibition of ferroptosis. Furthermore, our in vitro and in vivo studies demonstrated that treatment with statins, such as atorvastatin and simvastatin, induced ferroptosis and sensitized radioresistant HNSCC cells to irradiation, improving radiosensitivity and potentially enhancing the response to RT. Additionally, in xenograft models, the combination of statins and RT led to a significant reduction in tumor initiation. These findings provide valuable insights for enhancing treatment and improving prognosis in HPV‐negative HNSCC by targeting ferroptosis and utilizing statins to sensitize tumors to RT‐induced cell death.

Knockdown of USP7 alleviates atherosclerosis in ApoE-deficient mice by regulating EZH2 expression

Abstract Atherosclerosis (AS) is a chronic vascular disease associated with lipid accumulation. Understanding the molecular mechanisms of AS is essential. Ubiquitin-specific protease 7 (USP7) is a deubiquitination enzyme involved in various cellular processes, including lipid metabolism. In this study, we aimed to elucidate the role of USP7 in AS progression and its underlying mechanism using ApoE-deficient mice. We found that USP7 ablation improved the morphological characteristics of AS in these mice. USP7 knockdown reduced inflammation, evidenced by decreases in inflammatory markers IL-6, TNF-α, and IL-1β by 35, 40, and 38%, respectively (p &lt; 0.01). Additionally, USP7 depletion reduced oxidative stress, indicated by a 30% reduction in malondialdehyde levels and increases in superoxide dismutase and glutathione peroxidase levels by 25 and 28%, respectively (p &lt; 0.01). Moreover, USP7 knockdown blocked lipid accumulation in aortic tissue cells. Mechanistically, USP7 knockdown inhibited enhancer of Zeste Homolog 2 (EZH2) expression, thereby suppressing AS progression. In conclusion, USP7 depletion alleviated AS progression in ApoE-deficient mice by targeting EZH2 expression. USP7 may serve as a therapeutic target for AS.

Resveratrol Protects Müller Cells Against Ferroptosis in the Early Stage of Diabetic Retinopathy by Regulating the Nrf2/GPx4/PTGS2 Pathway.

The aim of this study was to investigate the anti-ferroptotic effect of resveratrol (RSV) on retinal Müller cells (RMCs) in the early stages of diabetic retinopathy (DR) via the nuclear factor erythroid 2-related factor 2 (Nrf2)/glutathione peroxidase 4 (GPx4)/prostaglandin-endoperoxide synthase 2 (PTGS2). The retina was obtained from normal and diabetic Sprague-Dawley rats or wild-type and Nrf2 knockout (KO) diabetic mice, with or without RSV (10mg/kg/d) treatment for 12weeks. RMCs transfected with or without SiNrf2 were cultured with high glucose and RSV (20mM). The retinal neurofunctional changes were measured by electroretinogram (ERG). The retinal inner nuclear layer cell mitochondrial morphological changes were detected by transmission electron microscopy. The cell viabilities were measured by cell counting kit-8 (CCK-8) assay. The levels of Fe2+, malonic dialdehyde (MDA), and glutathione (GSH) were measured by colorimetric method. The expression of Nrf2, GPx4, and PTGS2 was detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunocytochemistry. In vivo, RSV inhibited retinal neurofunctional changes and mitochondrial morphological changes; decreased Fe2+, MDA, and PTGS2; and increased GSH, Nrf2, and GPx4 in retina of DM rats. In vitro, RSV decreased MDA and PTGS2 and increased cell viability, GSH, Nrf2, and GPx4. In vivo and vitro, the role of Nrf2-regulated signaling pathway in anti-ferroptosis by RSV was further confirmed using Nrf2 KO mice and pre-transfected SiNrf2 in RMCs. These findings indicated that RSV is a potential therapeutic option for DR and that Nrf2/GPx4/PTGS2 plays a role in the anti-ferroptosis mechanism of RSV on RMCs.

Angiotensin 1–7 restrains vascular injury of extracorporeal membrane oxygenation by inhibiting ferroptosis

BackgroundAngiotensin 1–7 (Ang1-7) is the classical end product of angiotensin II, which has the effects of dilating blood vessels, protecting endothelial cells, anti-hypertension, improving cardiac function, and inhibiting atherosclerosis. We hypothesize that Ang1-7 inhibits human umbilical vein endothelial cells (HUVEC) ferroptosis through NF-κB/P53 signal pathway, and reduces extracorporeal membrane oxygenation (ECMO) vascular injury. MethodsCultured HUVEC were seeded into 15 wells and randomly divided into five groups: the control group and four experimental groups (erastin, erastin + Ang1-7, erastin + Ang1-7 + Betulinic acid, erastin + Betulinic acid). After stimulation, cell viability, lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) activity were measured. The effects of Ang1-7 on HUVEC microstructure, antioxidant enzymes (ferritin heavy chain 1 (FTH1), cystine/glutamic acid reverse transport solute carrier family 7 members 11 (SLC7A11 or XCT), superoxide dismutase-2 (SOD-2) and glutathione peroxidase 4 (GPX4)), NF-κB, P-NF-κB, P53, and P-P53). ResultsErastin stimulation promoted HUVEC lipid peroxidation, decreased antioxidant enzyme expression, increased P-NF-κB, P53, and P-P53 expressions, and damaged HUVEC mitochondrial structure. Ang1-7 alleviated the effect of erastin on HUVEC, which was destroyed by Betulinic acid. ConclusionAngiotensin1-7 pretreatment inhibited vascular endothelial cells’ ferroptosis and alleviated ECMO vessel injury through NF-κB /P53 signal pathway.

Etomidate protects retinal ganglion cells from hydrogen peroxide-induced injury via Nrf2/HO-1 pathway.

To determine whether etomidate (ET) has a protective effect on retinal ganglion cells (RGCs) injured with hydrogen peroxide (H2O2) and to explore the potential mechanism underlying the antioxidative stress effect of ET. Cultured RGCs were identified by double immunofluorescent labeling of microtubule-associated protein 2 and Thy1.1. An injury model of H2O2-induced RGCs oxidative stress was established in vitro. Cells were pretreated with different concentrations of ET (1, 5, and 10 µmol/L) for 4h, followed by further exposure to H2O2 at 1000 µmol/L. Cell counting kit 8 and Annexin V/propidium iodide assays were applied to detect the viabilities and apoptosis rates of the RGCs at 12, 24, and 48h after H2O2 stimulation. The levels of nitric oxide, malondialdehyde, and glutathione in culture media were measured at these time points. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were performed to observe the effects of ET on the messenger RNA and protein expression of inducible nitric oxide synthase (iNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), glutathione peroxidase 1 and the level of conjugated acrolein in RGCs at 12, 24, and 48h after H2O2 stimulation and in the retina at 12h after optic nerve transection (ONT). The applications of 5 and 10 µmol/L of ET significantly increased the viability of RGCs. Results from qRT-PCR indicated a decrease in the expression of iNOS and an increase in the expressions of Nrf2 and HO-1 in ET-pretreated RGCs at 12, 24 and 48h after H2O2 stimulation, as well as in ET-treated retinas at 12h after ONT. Western blot analysis revealed a decrease in the expression of iNOS and levels of conjugated acrolein, along with an increase in the expressions of Nrf2 and HO-1 in ET-pretreated RGCs in vitro and ET-treated retinas in vivo. ET is a neuroprotective agent in primary cultured RGCs injured by H2O2. The effect of ET is dose-dependent with the greatest effect being at 10 µmol/L. ET plays an antioxidant role by inhibiting iNOS, up-regulating Nrf2/HO-1, decreasing the production of acrolein, and increasing the scavenge of acrolein.

Impact of weight variation on the microbiome of yak dams and calves

IntroductionLimited information exists regarding the microbiome composition of yak calves of varying weights. Therefore, this study aimed to investigate the microbiomes of mother-calf pairs with different weight profiles.MethodsFecal and blood samples were collected from both lower-weight (CB) and higher-weight (HB) yak calves, along with their corresponding female yaks (CA, HA).ResultsThe results revealed significantly higher levels of T-AOC (total antioxidant capacity) and GSH-Px (glutathione peroxidase) in HB animals (p &amp;lt; 0.001). Sequencing yielded 652,181 and 643,369 filtered reads in female and calf yaks, respectively. Alpha diversity analysis indicated that Chao1, Faith_pd, and Observed species were significantly higher in CA compared to HA (p &amp;lt; 0.01). Furthermore, nine genera were notably different between HA and CA yaks, including Avispirillum, Fimenecus, CAG-1031, Odoribacter 865974, and Jeotgalicoccus A 310962. Compared to CB yaks, CA animals exhibited significant differences in one phylum and six genera, including CAG-485 (p &amp;lt; 0.05), CAG-83 (p &amp;lt; 0.01), Copromorpha (p &amp;lt; 0.01), Phocaeicola A 858004 (p &amp;lt; 0.05), and UBA2253 (p &amp;lt; 0.05).ConclusionIn summary, higher-weight yak calves demonstrated increased oxidative resistance, and weight profiles were linked to the microbiomes of both female yaks and their calves. These findings offer valuable insights for optimizing yak breeding practices in high-altitude regions.

Short-term Uridine Treatment Alleviates Endoplasmic Reticulum Stress via Regulating Inflammation and Oxidative Stress in Lithium-Pilocarpine Model of Status Epilepticus

Background: Status Epilepticus (SE) leads to the development of epilepsy with the contribution of Endoplasmic Reticulum (ER) stress. Uridine, a pyrimidine nucleoside, has been shown to have neuroprotective and antiepileptogenic effects in animal models. This study aimed to determine whether uridine ameliorates ER stress and apoptosis following epileptogenic insult. Secondly, this study aimed to establish the effect of uridine on inflammatory and oxidative stress parameters that contribute to ER stress. Methods: Status epilepticus was induced using lithium-pilocarpine in adult male Sprague-Dawley rats. Following SE termination, rats were treated with uridine, 4-phenylbutyric acid (4-PBA), or saline twice daily for 48 h. Expressions of hippocampal glucose-regulated protein 78 (GRP78), Inositol- Requiring Protein 1 (IRE1α), Protein kinase RNA-like Endoplasmic Reticulum Kinase (PERK), and C/EBP Homologous Protein (CHOP) were determined by western blotting 48 h after SE. Uridine's effects on apoptosis, inflammation or oxidation were evaluated by analyses of cleaved caspase-3 and poly(ADP-ribose) polymerase 1 (PARP1) protein expressions or pro-inflammatory cytokine levels or levels of oxidative stress markers, respectively. Results: Expressions of all ER stress-related proteins significantly increased 48 h after SE. Uridine treatment markedly decreased GRP78, IRE1α, and CHOP levels. A decrease in the PERK level was observed following the administration of 4-PBA; however, uridine had no effect. Cleaved caspase-3 and PARP1 levels were increased in the SHAM group, while uridine and 4-PBA treatment effectively decreased their expressions. Treatment with uridine significantly reduced Myeloperoxidase (MPO) and Malondialdehyde (MDA) levels while tending to increase Catalase (CAT) and Glutathione Peroxidase (GPx) levels. Uridine treatment also significantly attenuated levels of TNF-α and IL-1β, the pro-inflammatory cytokines, which increased 48 h post-SE. Conclusion: Our data indicate that uridine alleviates ER stress after SE. This effect may be attributed to the regulation of inflammation and oxidative stress. Uridine shows promise as a potential preventive agent for epilepsy.